The general advice I like to give (and many others will agree) is to buy your backpack last. Buy the rest of your gear and then choose a backpack that holds it all and is comfortable. The disadvantage in buying the pack first is you will either end up with a pack that is too small/uncomfortable for the rest of you gear or you get a pack that is too big and bring along a lot more than you need because you have the extra space.

If you already have some gear, tell us what it is, and maybe someone will have a recommendation for you. Not to mention we just love giving advice on gear choices :).

It's an enlightening exercise to add up the weights for the choices that yield more "camp-comfort" and compare them to the weight of the choices that yield more "hiking comfort" (ie: lighter weight pack).

i have an Hennessy hammock, old school (really heavy) army surplus bag, small aluminum mess kit, enough clothes and rain jacket for 3-5 days. We will be carrying some of our own water and then use chemicals for other. and for food, we are going straight beef jerky as well as freeze dried meals for just two of us. Right now i have a Camelbak Kronos but i fear that that will be too small.

If you're just starting out, maybe size is less of an issue for you and cost is more of an issue? If you want a decent backpack that will be forgiving to a backpacking newbie, I think the Mountainsmith Boundary is a good choice. I just picked one up for winter backpacking and at 75L, 4lbs (after removing the top lid and a few straps), and $130 from Campmor, it's a darn decent backpack. If you're using an army surplus sleeping bag, I'd recommend a large volume pack like this.

However (to confuse matters, lol), for most of my own 3-season backpacking, with up to 4 days of food, I generally use a ULA Conduit, which is a 50 L pack and weighs 20 ounces, though that's a frameless pack (you have to use your sleeping pad internally as a frame), and really doesn't work that well when you're packing more than one set of clothes, a synthetic sleeping bag, or a tent...just not enough volume. For loads under about 25 pounds, however, it's a great pack.

what i'm really concerned about is how to pack my sleeping bag on there...i think that i should have ample room it's just that my sleeping bag is huge! (i know i have to get a compression sack for it)...there is just no where to strap it!

There are very few practical backpacks large enough to put that sleeping bag inside. It could maybe be done with an expedition size 85L pack, but you will suffer from too heavy, too expensive, and too large later on. You would be better off to invest in a smaller and lighter sleeping bag and rent an appropriate sized backpack from the Rec Program at Black Hills State.

Or if you are absolutely in love with that sleeping bag, get an external frame pack like Kelty makes, and put the sleeping bag in a large compression dry sack that you strap onto the frame under the bag.

Neither of these sound like UL setups, so you may not get a lot of meaningful advice here.

Maybe the best way to determine pack size (absent the opportunity to try out a bunch of packs) is to stuff your stuff into a bunch of garbage bags (don't forget to add food and water). I would buy a variety of sizes at the store and then see which one can handle all of your stuff (without excess space). I think that would give you a good idea the size of pack you need. A lot of packs have straps which allow you to tie stuff onto the outside, so you could probably make do if you buy a pack a bit too small. That way, you could still use the pack if you find yourself losing bulk (as well as weight).

As a general purpose, lightweight backpack, I recommend the Granite Gear Vapor Trail. At a bit over 2 pounds, there are definitely lighter packs out there (and ones that can hold more capacity) but I really like mine. The waste belt is great, the frame is strong and compression is really good. It has few bells and whistles, which to me is the essential part of ultralight backpacking. If you hunt around, you should be able to find one on sale somewhere. If you find that your stuff is too big for the Vapor Trail (which holds 3600 cubic inches) then I would recommend going to a different manufacturer. Unlike other companies (like ULA or Gossamer Gear, for example) Granite Gear doesn't seem to make any really big capacity, ultralight backpacks.

Your gear choices are typical of traditional (heavy) backpacking that I see with Boy Scouts. Look at REI.com for recommendations on pack size for various trips. From memory, I believe 4000-5000 cubic inches is the traditional recommendation for 3 day weekend trips - but check since I haven't looked in years...

However, you should be aware there is a better way ! Only carry as much clothing as you can wear at one time & need to keep warm sitting in camp in the evenings + 1 extra pair of socks. Wear running shoes & 2 pairs of nylon dress socks instead of boots & heavy wool socks. Wear a bathing suit with mesh underwear instead of shorts. Use very light insulation (fleece &/or polypro long johns) - but couple them with a wind shirt &/or wind pants. Couple your windsuit with a poncho instead of a full rain suit and pack cover. Get a 30-40 degree sleeping bag and use it as a quilt while wearing your fleece and wind suit. Use a big tarp and groundsheet instead of a tent (add a sleeping bag cover (bivy) in the cold, and a bug net in the summer). Keep the 1 liter pot from the mess kit and get a lexan soup spoon plastic cup (+ medium sized ziploc bowl if cooking for 2 people). Use a foam pad, but place it on soft stuff like grass, pine needles, leaves, etc. Use a butane or alchohol stove rather than white gas. Use Aquafina (etc) water bottles instead of Nalgene or Camelback bladders. For "other stuff" whittle it down to a 2" swiss army knife, some bandaids, ace wrap, 1st aid cream, burn cream, a bandana, duct tape, a headlamp, extra lighter and not much else.

Not sure if that was directed back at the previous poster, but if it's an open question: lots of trail running shoes are out there. I own a pair of Vasque Velocity shoes. They're kind of heavy, but they fit well. That's a rare find when you're shopping in the size 15 range. I picked up a couple pairs of Montrail Hardrocks and Nitrus on SAC and am anxiously awaiting them to hit my mailbox. You can do a web search for "trail running shoes review" for several names of shoes. Do your homework and read some of the posts. A bonus would be to find a local shop that may stock them for you to try on before purchase. One thing I liked about the steepandcheap.com site is they claim a warranty as long as you keep the tags and fill out an RMA. I've not tested them on it, but I will if the Montrails don't fit.Of all the things you use most in life, take care of your feet. If you don't, you will be reminded in every step.

Trail running shoes have more aggressive lugged soles (for traction in mud), slightly more stable "pryamid-shaped" heel foam &/or plastic "lateral stability" plates on the sides of the heel / sole junction, and a more rigid piece of plastic under the arch (so you don't feel the rocks).

New Balance 806's have been a historical favorite of the ultra-lite crowd, but it's because they last slightly longer and this is more important on multi-month "thru-hikes" of the appalachian trail, pacific crest trail, etc. It's MUCH more important to get something that fits perfectly than a little more durability though.

Also, a standard recommendation is get a pair 1/2-1 sizes too big since your feet will swell when you walk all day. For the same reason, a little extra width in the toe area is a very good thing. Err toward the 1 size too big if your pack is heavy rather than light. (This same recommendation holds true for boots too). You just lace them a little tighter at the beginning of the day so your foot doesn't slide around and cause blisters.

If your pack is really heavy, AND you have weak ankles that tend to sprain (or roll under) easily then light fabric boots that come up just over the ankle are probably better than running shoes. Just remember that airy and light is much better than waterproof and leather. I try to get my Scouts packs to 10-15% of their body weight, since otherwise they don't have a good time, and their shoulders and hips get really sore by day 3. At 15% of your body weight, running shoes are fine for everyone. At 25% of your body weight, running shoes are still fine unless you have extra weak ankles.

If it's not that cold in June, you may be able to get away with the comforter you use on your bed at home in the winter - as long as the shell and insulation are not cotton. It's not nearly as small and light as a 30-40 degree sleeping bag, but anything would be smaller and lighter than the heavy canvas, qualofill and #12 brass zipper on the military bags...

ps: You'll need the foam pad under you to stay warm in a hammock when the temperature is around 60-65 degrees or less. 24-26" wide ones work best for a hammock.